What's the difference between atmospheric and ground-level ozone?

Atmospheric ozone is found in the stratosphere, while ground-level ozone is a pollutant in the troposphere.

Atmospheric ozone, also known as stratospheric ozone, is a naturally occurring gas found in the upper layer of the atmosphere, the stratosphere. It plays a crucial role in protecting life on Earth by absorbing most of the Sun's harmful ultraviolet (UV) radiation. This layer of ozone is often referred to as the ozone layer. The concentration of ozone in the ozone layer is quite small, but it is vitally important. Without the ozone layer, the Earth's surface would be exposed to significantly more UV radiation, which can cause skin cancer and cataracts in humans, and harm animals and plants.

On the other hand, ground-level ozone, or tropospheric ozone, is not naturally occurring and is considered a harmful air pollutant. It is created by chemical reactions between oxides of nitrogen (NOx) and volatile organic compounds (VOCs). This reaction happens when pollutants emitted by cars, power plants, industrial boilers, refineries, chemical plants, and other sources chemically react in the presence of sunlight. Ground-level ozone is a primary component of urban smog and can cause a variety of health problems, including chest pain, coughing, throat irritation, and airway inflammation. It can also worsen bronchitis, emphysema, and asthma.

In summary, while both atmospheric and ground-level ozone share the same chemical formula (O3), their location in the atmosphere and their impact on the environment and human health are vastly different. Atmospheric ozone in the stratosphere is beneficial as it shields the Earth from harmful UV radiation. In contrast, ground-level ozone in the troposphere is a harmful pollutant that contributes to respiratory problems and other health issues, as well as being a component of smog.